Control for electric fuel pumps



Feb. 27; 1945.

A. c. KORTE ETAL CONTROL FOR ELECTRIC FUEL PUMPS Filed Nov, 3 19 '1?? ZIIHHHI QIMMHF- INVENTOR ALFRED C. KORTE KENNETH LANN RT 00% ATTORNEY Patented iFeb. 27, 1945- CONTROL FOR ELECTRIC FUEL PUMPS Alfred C. Korte, St. Louis, and Kenneth Lannert,

St. Johns Station, Mo., assignors to Carter Carburetor Corporation tion of Delaware Louis, Mo., 9. corpora- Application November 3, 1941, Serial No. 417,726

1 Claim.

This invention relates to control devices for electrically driven motor vehicle accessories and more particularly to safety switch devices for controlling electrically driven fuel pumps. It is a continuation, in part, of our co-pending application, Serial No. 291,588, filed August-23, 1939.

The present invention has for its primary object the provision of a safety switch device for controlling an electric fuel pump."

It is a further object of the present invention to provide a safety switch device of the above character arranged to be operated by pressure developed by an engine lubricatin oil pump.

It is a further object of the present invention to provide, in combination, with an oil pressure operated switch of the above character a second switch device arranged to co-act with the engine starter switch whereby the electric fuel pump may be energized during the cranking of the engine and before sufficient pressure is built up by the engine lubricating oil pump to close the oil pressure operated safety switch device.

Still another object of the present invention is to provide in series with the above mentioned oil operated switch a second safety switch device responsive to the suction in the engine intake manifold and which is arranged to break the fuel pump circuit when the intake manifold vacuum drops due to engine inoperation.

'Other objects and advantages will become apparent upon reference to the following description and accompanying drawing, referring to which Fig. 1 diagrammatically illustrates one form of the present invention. In this form, a simple battery circuit for driving the electric fuel pump is illustrated and includes, in series, a suction operated switch and a switch which is operated by lubricating oil pressure.

Fig. 2 diagrammatically illustrates a second form of the present invention. In this arrangement, parallel circuits for energizing the electric fuel pump are shown. In one of these circuits is interposed a safety switch device operated by lubricating oil pressure; in the other of these circuits is interposed a switch which is manually operated and arranged to co-act simultaneousl with the engine starting motor switch.

Referring to the arrangement shown in Fig. 1,

numeral l indicates a fuel storage tank having an electrically driven centrifugal type fuel pump 2 mounted therein. Fuel is supplied to the carburetor 5 by pump 2 through discharge pipe 3 and conduit 4. A source of electrical energy for the operation of fuel pump 2 is indicated at 6. The

leads I, 8, 9 and I0 form a battery fuel pump circuit. Interposed in this circuit is a switch device ll having'a spring l2 which normally urges the switch toward a circuit breaking position. The switch device if further comprises a cylinder l3 having a plunger N mounted therein. The cylinder I3 is connected at its upper end by means of conduit l5 to the pressure lubricating system of an internal combustion engine (not shown). Also interposed in the circuit in series with switch H is a second safety switch device, generally indicated at l6? Switch I6 is normally held in a circuit breaking position by spring l1.

Switch device l6 further comprises a cylinder i8 having a plunger l9 mounted therein. The upper end of cylinder [9 is connected to the intake manifold of an internal combustion engine (not shown in this figure) by means of conduit 20.

Also interposed in the fuel pump circuit is a manual switch device, generally indicated at 2|. The operation. of the arrangement shown in Fig. 1 is as follows:

Whenmanual switch 2| is closed and the engine is operating under its own power, sufficient pressure will be developed by the lubricating oil pressure system to force plunger l4 downward and close the switch device ll. Also during operation of the engine the switch device I6 will be closed by reason of intake manifold vacuum.

When the engine is turned off or ceases to operate for any reason,'the fuel pump circuit will be broken at H and IE or if either of these switches, for some unaccountable reason, does not function, the circuit will be broken by the other of the switches.

Referring to the arrangement shown in Fig. 2,

, numeral 2 l a generally indicates an internal combustion engine having a carburetor 5 mounted thereon. A fuel supply tank is generally indicated at I, having an electrically driven centrifugal fuel pump 2 mounted therein for supplying fuel through conduit I4 to the carburetor 5. The engine 2 la is provided with an electrically driven cranking motor indicated at 22 and an engine driven generator indicated at 23. A circuit for energizing the cranking motor 22 is provided and comprises a storage battery 6, and leads 23, 24 and ground leads 25 and 26. Interposed in this circuit is a relay switch device, generally indicated at 21. Switch 21 is electromagnetically operated and includes a solenoid winding 28. An

leads II, II, the switch blade SI and leads 8! and 38.

A circuit for energizing the electric fuel pump 2 is provided and includes the storage battery I, leads I, 34, 3B and ground leads I. and 28. Interposed in this circuit is an oil pressure operated safety switch device, generally indicated at 31. Switch 31 comprises a switch blade 38 for connecting leads 34 and 35. The switch is normally circuit is a manually operated switch device generally indicated at 45. Switch- 45 comprises a switch blade 3| .which is normally held in a circuit breaking position by means of a spring 46.

A by-pass of the switch device 31 is provided and comprises the lead 30 and the switch blade 3i, and lead 41. It will be seen from this that although switch 31 may be in an open position, the fuel pump battery circuit may be closed through the by-pass by closing the manual starter switch 45.

The operating arrangement shown is as follows:

Upon starting an engine, the manual ignition switch, generally indicated at 48 is closed. The circuit for energizing starting motor relay switch 21 is then closed by closing switch 45, thus causing the engine to be cranked. Although the oil pressure may be insuflicient during the cranking period to close switch 31, the fuel pump 2 will, nevertheless, be energized through the by-pass by inFig. 2

- reason of the switch 48 being closed.

As soon astheenginehasbeguntorimimderitsown power, suiilcient lubricating oil pressure will be built up to close switch 81 which will remain closed during all normal operation of the engine. If the engine should, subsequently, become stopped and the manual ignition switch 4| be left closed inadvertently, the fuel pump circuit will, nevertheless, be broken as the oil pressure drops by reason of spring 8|. The by-pass of switch 31 will, of course, be open at all times except during cranking of the engine.

The foregoing description and drawing are intended to be illustrative and not limiting and the exclusive use of all modifications of the present invention within the scope of the appended claim is contemplate.

We claim:

In combination, an internal combustion engine, a pressure lubricating system for said engine, fuel supply means including an electrically driven fuel pump, a starter switch for said engine, said starter switch closing a starting circuit including a source of power, a starting motor, and said electric fuel pump, whereby fuel is supplied said engine during starting operation, a main power circuit for said pump independent of control by said starting switch for continuing operation of said electric fuel pump after said starting switch is opened when said engine starts, said main circuit including a pressure switch, said pressure switch being closed to complete said main circuit by pressure developed when said engine starts, and breaking said main circuit to stop said pump when the pressure developed by said engineis interrupted due to stopping of said engine.

ALFRED C. KORTE. KENNETH LANNERT. 

